• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.5
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• pp.847-856
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• 2016

Recently, with a high level of economic growth, rapid urbanization, population, environment and housing problems were accompanied in Korea. In particular, the traffic problem has become a serious social problem. As the current transportation policy has been carried out, concentrating on traffic flow, in 2015, death rate for pedestrians while walking (1,795 persons) is 38.8% compared to entire death rate in car accident (4,621 persons), so there is need to solve it. Although, crosswalk should make pedestrian cross it safely, it has been made on the basis of the width of road without exact standard for current width of the crosswalk and the location of stop line. Moreover, in the area around many campuses or commercial facilities, crosswalks are set with not considering pedestrian passage, but designed uniformly. Therefore, the purpose of this study is to estimate reasonable dimension of crosswalk considering pedestrian traffic and walking speed and it makes the accident rate lower in the crosswalk, which has a lot of problems including decisions of vehicle traffic signal time, lack of pedestrian's signal timing, pedestrian's crossing of long-distance. The following are the methodology of the study. Firstly, for crosswalk calculation of specifications, examination relating existing regulations and researches dealing with crosswalk, pedestrians and stop line is needed. After analyzing problems of current width of crosswalk and stop line, present the methodology to calculation of specifications and basing on these things, calculation of specifications for crosswalk will be decided. In conclusion, the calculation of specification and improvement of stop line for crosswalk laid out in this study are expected to be utilized as base data in case of establishing relevant safety facilities and standards.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.3
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• pp.239-245
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• 2016

In the midst of continuing international recession, the rate of maritime traffic and marine leisure markets are consistently growing. The Republic of Korea controls the marine traffic volume through vessel traffic centers and various other management facilities. Nevertheless, the continuous growth and complexity of marine traffic is resulting in repeated occurrences of marine accidents. Recovery is very difficult in cases of human injuries or deaths caused by marine accidents due to its nature, and the scale of marine accidents is also becoming greater with advanced ship building technologies. Passenger ships, oil tankers, and other such vessels used for specific purposes requires a more detailed navigational status surveillance and analysis, and numerous research has been conducted with an objective for monitoring such special purpose vessels. However, the data elements transmitted from the ocean to the shore station are limited to AIS and ARPA. We are implementing IoT ship sensor collection and a syncing system capable of transmitting various ship sensing data to the shore station, and also proposing a Safe Navigation Status Analysis System utilizing the collected data.

• Journal of Navigation and Port Research
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• v.26 no.4
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• pp.363-372
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• 2002

Recently, mutual economy cooperation in Northeast Asia has leaded steady growth among main countries of it and rather promoted a single economy circle. In this region, Busan container port competes with min container ports in China, Taiwan and Japan in it for attracting transshipment container traffic of north-Shanghai in China and for-east Russia. Therefore, this paper aims to suggest competitive strategies for Busan container port to attract container traffic in Northeast Asia To do so, it evaluates the preference of important ports in the competitive situation and competitiveness edgy of important ports in Northeast Asia, and finally proposes the relative order of important factors. Based on the evaluation of it, first, the Busan ports hue tn strengthen port facilities to attract more traffic and in detail, reinforce the number of berth, yard areas and handling equipment Second, they also have to provide high quality of services to deliver cargos in time, not being damaged and swiftly response to shipowner and shipper's claim, Third, they need to review the strategy to adopt flexible tariff policy and to invest the profit from tariff in port service and facilities, as providing higher port tariff level by a regular rate.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.1
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• pp.92-100
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• 2016

It is informed that the Voice over LTE(VoLTE) which serves voice and message on IP networks is better in terms of economies of scale than the legacy voice service on 2G/3G circuit-switched networks because of its technological and cost efficiency. In addition, services of voice and data are running on a single LTE network and as a result VoLTE has the more economies of scope. But, there is no study about how much technology-efficiency VoLTE has compared to circuit-based voice service and how much voice charge can be reduced as VoLTE grows up. This paper analyzes empirically cost-efficiency of VoLTE against circuit-based voice service and quantifies the reduction of voice charge as 2G/3G voice traffic shifts to VoLTE. The results describe the first is that the average cost of the total voice traffic rises shortly just after the investment of LTE network for providing VoLTE but it will soon have a capacity available to reduce the charge due to VoLTE's outstanding cost efficiency on the assumption that voice traffic is fixed, and the second is that the charge can be cut to 60% of the current rate in case of all the voice traffic moves to VoLTE. The latter proves partially the validation of data-focusing pricing plan. Our results are expected to become basic data for network operators' establishing pricing strategies and for policy makers' inducing price cutting.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.10
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• pp.937-945
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• 2014

As various services requiring high data rate are supported by introducing LTE/LTE-adv., mobile traffic increases rapidly. To cope with the continuous growth of traffic demand, small cell technology is considered as one of the most promising one. Small cell can increase system capacity by increasing the number of base stations with reduced cell radius. In this paper, we analyze the effect of cell densification with small cells in terms of SINR and average UE throughput considering cell split and the number of UE per unit area. As the cell becomes smaller, SINR degradation arises from high ICI(Inter Cell Interference) and we evaluate the effect of interference mitigation scheme in small cell environment where the proper interference mitigation technique is applied.

• IEMEK Journal of Embedded Systems and Applications
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• v.10 no.4
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• pp.241-255
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• 2015

Recent network environment has been rapidly evolved to cloud computing environment based on the development of the Internet technologies. Furthermore there is an increasing demand on mobile cloud computing due to explosive growth of smart devices and wide deployment of LTE-based cellular networks. Thus mobile Desktop-as-a-Service(DaaS) could be a pervasive service for nomadic users. In addition, video streaming traffic is currently more than two-thirds of mobile traffic and ever increasing. All such trends enable that video streaming in mobile DaaS could be an important concern for mobile cloud computing. It should be noted that the performance of the Transmission Control Protocol(TCP) on cloud host servers greatly affects Quality of Service(QoS) of video streams for mobile users. With widely deployed Linux server platforms for cloud computing, in this paper, we conduct an experimental analysis of the twelve Linux TCP variants in mobile DaaS environments. The results of our experiments show that the TCP Illinois outperforms the other TCP variants in terms of wide range of packet loss rate and propagation delay over LTE-based wireless links between cloud servers and mobile devices, even though TCP CUBIC is usually used in default in the current Linux systems.

• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.7-16
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• 2002

Rapid growth rate of container traffic in China has caused the fierce competition to attract Trans-shipment Container Cargos from/to China among competitive ports in Asia. Therefore, this paper aims to suggest some strategies to attract them from/to China by Korea ports. To do so, it evaluates the preference of important ports in the competitive situation and the competitiveness of important ports in Asia, and finally proposes the relative order of important factors. Based on the evaluation of it, Both the Pusan and the Kwangyang ports have to strengthen port facility to attract move traffic and in detail, reinforce the number of berth, yard areas and handling equipment. they also have to provide high qualify of services to deliver cargos in time. not being damaged and swiftly response to shipowner and shipper's claim.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.15-18
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• 2003

Recently, some researches related to air pollution problems in large cities of the Islamic Republic of Iran have been done. Famous institutes and research centers in countries like Japan, Sweden and Germany have been in cooperation with Iranian institutes in implementing the results. Due to quick increase in the population because of peoples＇ migration from countryside to cities, and rate of growth in the early years after the revolution, air pollution was an important problem in I.R.Iran. Therefore, air pollution control is one of the main issues in major cities of I.R. Iran. It is the purpose of this study to investigate the control mechanisms for air pollution problems in the major industrial cities. The necessary action plans that were taken in recent years in some of the cities, which were also suggested to be taken in the other ones, are the other purpose of this study. From the results of studies it was obtained in Iran, lots of researches are important to mention. Amongst the main activities that are done in recent years are： establishing of the meteorological research centers and atmosphere sciences; three applicator meteorological research centers and more than 40 new stations in the country; installation of newest computer systems in metrological information, using of wall map and continuous radio-traffic to announce traffic news; completing of subway construction in Tehran; forbidding of industrial activities in a definite distance away from Tehran and transferring them to suitable places; building of highways and freeways; improving of public transportation and gasifying them; developing of fuels quality and removing lead from them; and gasifying of the heating systems in houses and buildings.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.3
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• pp.617-624
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• 2015

The conflict of opposing pedestrian traffic-flow in a subway station(made up of stair, passageway, and escalator) diminishes the convenience and mobility of its users. In addition, the station's efficiency would be negatively affected by the growth of delay and queue length in pedestrian facilities. As these phenomena have been resulted by the overlapping in pedestrian's traffic-line, the separation of it would alleviate these problems. For the criteria and methodology of separation, this paper has investigated the bi-directional queue length and delay on the entrance of each facility (stair, passageway and escalator). Since the pedestrian flow exists bidirectionally, we have used the weighted average by inflow rate for the delay value. For the optimization of the separation, the Genetic Algorithm has been utilized in order to minimize the delay.

• Journal of Korea Port Economic Association
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• v.23 no.2
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• pp.1-24
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• 2007

With its foreign trade rapidly expanding and with economic growth continuing at a substantial rate, China has become the largest container traffic generating country in the world. And with trend of container ships becoming larger and faster, the environment surrounding ports in North-East Asia are rapidly changing. The Yangsan, offshore port for Shanghai, being developed on the islands of Da Yangsan and Xiao Yangsan, some 30km offshore, and connected to the mainland by the six-lane highway Donghai bridge, opened phase one in late 2005 and phase two in 2006 respectively and will have 29 berths by 2012 and be able to handle 15 million TEU. The Port of Shanghai which passed Busan in terms of container volume further consolidated its position as the world's No. 3 port with an annual volume of 21.7 million TEU in 2006 and is likely to have emerged as the biggest container port in the world. The Port of Busan, the world's fifth largest container port, wants to survive as regional hub port. In this circumstance, the strategies of the Port of Busan should be established.